The long-range goal of this project is to investigate how anesthetic agents influence the renin-angiotensin system and the peripheral sympathetic nervous system and to define more precisely how these two systems interact during anesthesia in the rat. The first step in the project will be to determine plasma renin activity at equipotent anesthetic concentrations and then to use specific inhibitors of the renin-angiotensin system to define the influence of this system on blood pressure. The second step will be to isolate the peripheral sympathetic nervous system from central influences in the intact animal through chemical ablation of descending noradrenergic and adrenergic nerves. Anesthesia will then be induced in these chronically prepared rats with and without inhibitors of the renin-angiotensin system. Important aspects of the study include: (1) quantitate renin activity and function with various anesthetic agents, (2) evaluate dopamine beta-hydroxylase as an index of sympathetic nervous system activity and, (3) quantitate central versus peripheral sympathetic nervous system function with various anesthetic agents. The data will allow subsequent investigation of the influence of anesthetic agents in pathologic disease states where hyperactivity of one or of both systems is thought to exist.